I’ve never given a thought to cancer in elephants until researchers at the University of Chicago last week revealed a partial explanation for why elephants are cancer resistant… only about 5% of them die of cancer compared to humans who have 11-25% cancer mortality across different populations.
Because larger animals have more cells and usually live longer than smaller ones, you might expect there to be more opportunity for them to develop cancer. But there’s no connection between body size, lifespan and cancer risk across animal species. This surprising phenomenon is called Peto’s Paradox after the epidemiologist Richard Peto who in 1975 noticed mice and humans have a fairly similar risk of developing cancer despite their vast differences in size and lifespan.
Through evolution, large animal species appear to have developed ways to decrease their cancer risk. Different animals have evolved along various lineages which means a number of mechanisms are probably involved in cancer resistance. Researchers are keen to understand cancer protection processes in order to provide insights into how cancer develops and potential cancer prevention strategies. Studying elephant genetics is providing some significant clues.